Rotatory magnet actuator



July 3, 1956 c. B. WALWORTH ET AL 2,753,474

ROTATORY MAGNET ACTUATOR Filed March 3l, 1951 United States Patent ROTATORY MAGNET ACTUATOR Clarence B. Walworth, Rocky Hill, and George A. Winterburn and Leroy E. Lawrence, Putnam, Conn.; said Walworth and said Lawrence assignors to said Winterburn Application March 31, 1951, Serial No. 218,632

Claims. (Cl. 310-104) This invention relates to magnetic transmission devices particularly applicable to switches such as are used to make and break electrical circuits.

Objects of this invention are to provide a transmission link having the general effect of cams or gears which is positive in action, which does not require mechanically contacting cams or has to rely on spring action, which is not subjected to mechanical Wear, which can be operated directly from the end of a rotating shaft, which will operate in either direction of rotation of the shaft, which will operate at a high rate of speed and in any position, which permits the location of actuating and actuated components in compartments hermetically sealed from each other, which can be arranged to operate a driven element at rates which are multiples of the rotational speed of the driving element, and which is rugged in design and simple and economical in construction.

In a broad aspect the invention contemplates a transmission link which has a driving member and a driven member, magnetic bodies with pole defining end positions, such as horseshoe magnets mountedv on the members with the pole portions of the magnetic bodies on respective members facing each other, means for movement of the members relatively to each other in a path wherein, upon this movement, the polarities of the pole portions change relatively to each other as they pass on the path, and which has means for mounting the members for relative movement in a path transverse of the first path, whereby the relative change of polarity of the pole portions passing each other in the first path is transmitted as movement ot' the other member in the second path, due to the continuous change between attraction and repulsion of the pole portions, which continuously maintains a force between the members without the assistance of springs or other biasing means. In a particularly useful embodiment, one of the members carries an electric switch element such as O a pair ot contacts or a conventlonal mercury switch Wherein a pool of mercury completes the electrical circuit through the switch element. In either case the switch element is arranged so that moving of the member carrying the element results in the operation or transfer of the contacts or mercury to either complete or interrupt the circuit through the switch.

In a more specific aspect one of the members is rotatory and the second member, which carries the actuated element such as a switch component, is pivotally mounted or otherwise secured for movement transverse to that of the rotatory member, for example in a direction substantially parallel to the axis of rotation of the rst member. The magnetized portions or magnets attached to the respective members are arranged so that the north and south poles of the magnets alternatively attract and oppose each other as the rotatory member is driven, for exampie, by means of an external rotating shaft thereby to move the other, pivotally mounted member back and forth alternatively to effect a movement such as to malte and break a circuit through a switch element.

In. another aspect a barrier of nonmagnetic material,

2,753,474 Patented July 3, 1956 for example of copper or a suitable dielectric is interposed between the magnetic portions of the respective members. This barrier can be extended to the wall of an enclosing housing and hermetically sealed thereto so that either driving and driven element is isolated from the ambient atmosphere without the use of a shaft seal or gland.

In a still further aspect two or more magnets are attached to one of two relatively movable members and oriented in opposite polarity with respect to adjacent magnets so that alternate north and south poles move in a locus defined by the relative motion of the members. The other, for example pivotally mounted or otherwise transversely movable member carries two magnet poles of op-f posite polarity and spaced at a distance approximately equal to or a multiple of the distance of two equal poles of the magnets carried by the other member. As one member is driven, successive pairs of magnets carried thereby are brought adjacent the magnets upon the other member thereby to move that member back and forth at a rate which is a function of both the speed of the first member and the number of pairs of poles carried thereby.

These and other objects and aspects of the invention will be apparent from the following description of several embodiments which refers to a drawing wherein- Fig. l is a plan View of one embodiment of the invention with the cover removed;

Fig. 2 is a sectional view on line 2 2 of Fig. l;

Fig. 3 is a sectional view similar to that of Fig. 2 of a second embodiment of the invention having a barrier separating the respective magnets;

Fig. 4 is a fragmentary view of a third embodiment of the invention incorporating a mercury switch;

Fig. 5 is a plan View of a fourth embodiment of the invention with the cover removed; and

Fig. 6 is a side elevation view with the housing broken away of the fourth embodiment of the invention which is shown in Fig. 5.

The specific embodiments of the invention chosen for the purpose of illustration are switches arranged to be operated by means of a exible shaft driven by a rotating machine element and are particularly adapted for the operation of electric counters, flashers and safety shut off devices such as for example commonly used in the textile industry, although it is to be distinctly understood that apparatus other than switches can be actuated in the manner according to the invention and that the principles of operation involved are not limited to the specific applications herein described.

As is shown in Figs. l and 2 the lirst embodiment of the invention comprises a substantially cylindrical housing iti the upper end of which is closed by means of an outwardly dished cover 12 secured by several screws 14. The bottom of the casing 1t) is closed by an integral wall or head .i6 having a boss i8 extending downwardly from the center thereof. The boss 1S is bored to receive the outer races of two ball bearings 20 which are held in place by means of respective set screws 22. The inner races of the bearings 2t) are forced on a rotatory member such as tbe shaft 24 whose upper end is provided with threads t0 receive three check nuts 26 which serve to maintain the inner races in position. The lower end of the shaft is also threaded to receive a lock nut 28 and a coupling, for example at the end of a flexible shaft, which coupling is not shown.

The end of the shaft Z4.- has an axially disposed threaded hote for a screw 3f which secures a magnet 32 of nia- 'I 'The ice ferial having a high coercive force, such as Alnico. magnet 32 is cylindrical in shape and is provided with a traverse slot which, horseshoe fashion, separates the north and south poles. immediately above magnet 32 is mounted a similar magnet 34, upon a second movable member such as the pivotally mounted arm 36. The

36 is pivotally supported at one end by means of a pin A40 which passes through downwardly bent ears at the end of the arm and corresponding apertures in -ears bent lat- .erally from one upright leg 42 of a U-shaped member 43. The opposite leg 44 of the U-shaped member acts as a stop for the end of the arm 36. The cross piece 46 of the U-shaped member is soldered or otherwise secured to a disc 48 which is in turn fastened to the bottom 16 of housing 10 by two screws 50.

The arm 36 carries a movable contact 52 upon one end of a flexible member 54 which provides wipe for the contact. The opposite end of the spring 54 is spaced from the arm 36 by means of an insulating piece 56 which provides electrical insulation therebetween, The arm and the spring are fastened together by rivets 58 with suitable insulating washers.

A stationary Contact 60 which is associated with the movable contact 52 is attached to the end of a screw member 62 which in the turn is threaded into the horizontal leg of an I -shaped piece 64. The vertical leg 64a of the L-shaped piece 64 is riveted to an upright plastic piece 65 which is in turn riveted to the leg 44 of the U-shaped member which also acts as a stop for the arm 36 described above. This plastic piece 65 is provided with an aperture through which the flexible member 54 carrying the movable contact 52 extends with appropriate clearance permitting the contacts to operate. Electrical connection from any external circuit to the stationary contact 60 is made by means of a conductor 66 one end of which is soldered to a tab extending from the vertical leg of the L-shaped piece 64 and whose other end is secured beneath a terminal screw 63 by means of a lug 70. The movable contact 52 is connected witha similar terminal screw 72 by means of a iiexible conductor 74 whose ends are soldered respectively to a lug '76 and the exible member 54. The terminal screws 68 and 72 are threaded into a plastic terminal block '7S which is fastened to the side of the housing 10 by means of a screw 80. The switch can be connected to external leads by means of conductors connected to terminal screws 68 and 72 after being brought in through a threaded aperture 82 in the side of the boss 84 extending from the side wall of the housing which is adapted to receive a connector associated with a thin wall conduit or an armored cable.

If the transmission link is used, as mentioned above, with an electric counter, its switch 52-60 is connected in the counter circuit by means of the terminal screws 63 and 72. The shaft 24 is connected by means of a ilexible shaft (not shown) with a rotatable element such as the main drive shaft of the machine to be supervised.

vRotation of the shaft 24 rotates magnet 32 so that the north and south poles thereof are in one position brought adjacent north and south poles of the magnet 34 carried by the arm 36 with the magnetic uxes of the magnets Y' opposing each other so that the arm 36 is moved upwardly about the pin 4t) to close the contacts 52 and 6G.

Upon continued rotation of the magnet 32 its north and south poles become adjacent the south and north poles respectively of the magnet 34 so that the magnets are Vattracted and arm 36 is moved downwardly, opening contacts 5.2 and 60.

AIt will `be particularly noted that no biasing spring or gravitational force is required, the force transmission being without causing wear of any of the moving parts.

Another advantage of linkages according to the invention is illustrated by a switch shown in Fig. 3. This second embodiment o-f the invention is described with reference to corresponding indicia designating similar parts shown in Figs. l, 2 and 3. In this instance the supporting disc 48a is made of a nonmagnetic material such as copper or a suitable plastic so as not to interfere with the magnetic circuit and is supported upon a raised step in the housing 10a. The step 90 is high enough so that the disc 48a is interposed as a barrier etween magnets 32, 33 carried by the members 24, 36. ln this modification the U-shaped member 43 can be divided into two parts one of which, designated 42a, carries the pivot pin 40 for the arm 36 and the other of which, designated 44a, carries the upright plastic piece 66a. These two parts 42a and 44a are riveted to the plate 48a. By soldering or otherwise sealing the disc 68a to the step 90 it is possible hermetically to seal the compartment containing contacts 52 and 60 so that the device can for example be used in explosive atmospheres without danger and without the necessity of using a gland or other shaft seal.

It will be understood that the barrier or septum 48a does not necessarily have to serve as a support for the transversely moving member, but that the supporting and separating functions can be performed by distinct elements of construction.

A further modification of the invention is shown in Fig. 4 wherein the contacts 52 and 60 are replaced by a conventional mercury switch 92 which is secured to the top of the movable arm 36h by means of a spring clip 94. The remaining elements of the switch are similar to those described in detail heretofore with respect to the first embodiment of the invention and designated accordingly, so that a more detailed description of structure and operation is unnecessary.

A fourth embodiment of the invention is shown in Figs. 5 and 6. This embodiment involves the change of speed between driving and driven members. The driving member is again a shaft 24 which has secured thereto a circular plate 96 whereupon are fastened three pairs of magnets 32C with oppositely facing poles. These magnets are equally spaced from each other and rotate in a circle centered on the axis of rotation of the shaft. Adjacent magnets are oriented so that successive magnets have their opposite poles turned upwardly, as indicated at N and S of Fig. 5. Another movable member such as the arm 36C is pivotally connected to the arms of a U-shaped bracket 42C by means of a pin 40. The web portion of the bracket 42e is attached to the inner surface of the wall of the housing 10 by means of a screw 98. The adjustable screw 62 of the stationary contact 60 is Vthreaded into the upper arm of a bracket 100, the lower bracket arm acting as a stop for the movable arm 36C. The arm 36e is provided with a cross piece 102 on whose ends are arranged two magnets 34C oriented with their polarity in the opposite sense so that one faces the rotating magnets with its north pole and the other with its south pole, and spaced at a distance equal to the diameter of the circle defining the path of the magnets 32C carried upon the disc 96.

Flrom the above it will be apparent that as each pair of opposed magnets 32e is by the rotation of the shaft 24, brought into position beneath the magnets 34e on cross piece 102, the magnets attract and repel each other alternately, the arm 36C moves up and down regardless of gravity and without assistance of any other biasing force, and contacts S2 and 62 are either open orv closed as the case may be depending upon the polarity of the magnets 34C. Three opening and closing cycles are completed during each revolution of the shaft, with the 2:6 ratio of magnets shown in Figs. 5 and 6. In general the relative rhythm of movement of members 24 and 36C is determined by the respective number of pole pieces.

It will now be understood that instead of a single U- shaped magnet, each of the relatively movable members such as 24 and 36 of Figs. l and 2 may carry several U- shaped magnets with alternating pole faces, or straight magnets mounted with alternate flux direction, in the manner described with reference to members 24 and 96 of Figs. 5 and 6.

It will be evident that, although switches according to the invention are particularly useful, the member travelling in the transverse path can be employed to actuate diverse apparatus such as mechanical counter input elements or signal iiags or relay actuators.

It will also be understood that the bar magnets of Figs. 5 and 6 can be replaced by appropriately arranged U-shaped magnets and that bar magnets can be used in the embodiment according to Figs. 1 to 4.

It should be understod that the present disclosure is for the purpose of illustration only and that this invention includes all modications and equivalents which fall within the scope of the appended claims.

We claim:

1. A force transmitting device comprising a driving member and a driven member; two continuously magnetized bodies with pole defining end portions, one body being mounted on each of said members with the pole portions of the bodies on respective members facing each other; means for continuously unobstructed movement of said driving member relatively to said driven member in a path common to all pole portions wherein, upon said movement, the polarities of said pole portions of the respective magnetic bodies alternate relatively to each other; and pivot means for mounting one of said members for rotatory movement in a path transverse of said common path; whereby said change of polarity upon movement of the members in the common path is transmitted as oscillatory tilting movement of the member in the transverse path, due solely to continuous change between attraction and repulsion of the magnetized pole portions.

2. Device according to claim 1 wherein each member carries a single U-shaped body of essentially the same shape as that of the other member.

3. Device according to claim 1 wherein at least one of said members carries several bodies defining a plurality of pole portions.

4. Device according to claim l wherein said members carry bodies defining even numbers of pole portions which numbers are different for the respective members.

5. Device according to claim 1 further comprising a housing on which one of said members is mounted for rotatory motion defining said common path and on which housing the other member is hinged for oscillatory motion defining said transverse path.

6. Device according to claim 5 wherein said housing is divided by a septum interposed between the pole portions of the respective members.

7. Device according to claim 6 wherein said septum supports one of said members.

8. A force transmitting device comprising a driving member and a driven member; two continuously magnetized bodies with pole defining end portions, one body being mounted on each of said members with the pole portions of the bodies on respective members facing each other, each body having an even number of pole portions of alternate polarity, and the number of pole portions on one body being a multiple of the number of pole portions on the other body; means for continuously unobstructed movement of said driving member relatively to said driven member in a path common to all pole portions wherein, upon said movement, the polarities of said pole portions of the respective magnetic bodies alternate relatively to each other; and pivot means for mounting one of said members for rotatory movement in a path transverse of said common path; whereby said change of polarity upon movement of the members in the common path is transmitted as oscillatory tilting movement of the member in the transverse path, due solely to continuons change between attraction and repulsion of the magnetized pole portions.

9. A force transmitting device comprising a housing; shaft means journaled on said housing; actuating means mounted on said shaft means within the housing and including permanent magnet means with actuating pole faces symmetrical to and in a plane essentially perpendicular to the axis of rotation of the shaft means; and actuated means mounted on said housing for rotation on a. pivot axis located outside said axis of rotation and parallel to said pole face plane, and including permanent magnet means with actuated pole faces opposite said actuating faces for tilting said actuated means on said pivot axis between an attracted and a repulsed position, said actuated pole faces being essentially parallel to said actuating pole faces and symmetrical to said axis of rotation; whereby rotation of the shaft means tilts the actuated means from attracted to repulsed position as the relative polarity of opposite actuated and actuating pole faces changes symmetrically with relative movement of the housing and the shaft means on said axis of rotation.

l0. A force transmitting device comprising a housing; shaft means journaled on said housing; actuating means `.ounted on said shaft means within the housing and including permanent magnet means with an even number of actuating pole faces of alternate polarity symmetrical to and in a plane essentially perpendicular to the axis of rotation of the shaft means; and actuated means mounted on said housing for rotation on a pivot axis located outside said axis of rotation and parallel to said pole face plane, and including permanent magnet means with an even number of actuated pole faces of alternate polarity, said number being unequal to said number of actuating pole faces, said actuated pole faces being opposite said actuating pole faces for tilting said actuated means on said pivot axis between an attracted and a repulsed position, and said actuated pole faces being essentially parallel to said actuating faces and symmetrical to said axis of rotation; whereby rotation of the shaft means continuously tilts the actuated means from attracted to repulsed position as the relative polarity of opposing pole faces changes symmetrically with relative movement of the housing and the shaft means on said axis of rotation, the unequal number of pole pieces providing a gear ratio between the rotatory and tilting movements.

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